Internal-combustion engine.



Patented Oct. 10, 1916.

2 Q /c ya 6 LF f H AQH. R. PULMAN.

INTERNAL COMBUSTION ENGINE.

APPLICATION FILED APR.12, 1915.

wzfzeskgegs To all wlwm z't may concern UNITED STATES .PATENT onirica.

i ARTHUR HARRY ROPER PULMAN,`OF LONDON, ENGLAND, ASSIGNOR O F `TWOTLIIRDS TO OLIVER PRESCOTT MACFARLANE, OF LONDON, ENGLAND.

INTERNAL-COMBUSTION ENGINE.

Be it known that I, ARTHUR HARRY RoPER PULMAN, a subject of the King of Great Britain, residing at "30 Victoria House, South Lambeth road, S. W., in the county of London, England, have invented v certain new and useful Improvements in or Relating to Internal-Combustion Engines,

' of which the following is a specication.

This invention has reference to internalcombustion engines, and relates more particularly to engines ofthe kind or class in which the working pressure is lexerted between the pistons or plungers moving 1n op posite directions in the working cylinder, and operating a single crank. j

A feature of the invention consists in simplifying the general construction of the engine and providing 2an arrangement of parts which more nearly resembles the standard construction of ordinary vertical or` marine steam-engines, by causing the two pistons to drive one and thev same crosshead which in .turn actuates the` crank.

A further Nfeature of the invention consists in arranging that the rear or auxiliary piston can be adjusted relatively to the front piston (or vice versa) in a very simple and convenient manner, so that the clearance between the two pistons can be varied to. enable the engine to work either with oil or gas as may bev desired. This adjustment can be eected without necessarily having to vary the length of stroke of the auxiliary piston, or to take the engine to pieces and b otll pistons may be made adjustable if des1re Another featureconsists in providing on the working cylinder, a pump cylinder the piston of whichmay be carried byy one of the working pistons, for instance the front or main pistbn. According to one example, the air-pump piston is connected to one end of a rockinglever or beam, the opposite end of which is connected by a side rod or rods to a sliding-piece constituting the cross- 'h'ead for the rod of the first mentioned or front piston, such cross-head driving the 'crank by a single main connecting-rod in the ordinary way, under the joint impulse of the two oppositely-moving pistons.y By coupling the main connectlng rod centrally .to the sliding-piece or cross-'head and mid- 'way between the front piston rod and the- Specification of Lettersifatent.

twisting strains on the cross-head are avoid ed. T he relative adjustment of the rear or auxlllary piston may be efected by making the rod which connects it to the rocking lever, adjustable in length, or the said rockmg lever may have an adjustable pivot or fulcrum to enable the throw to be varied as required withln certain limits.

A further feature of the invention conslsts in arranging the -sprayer or oil or spirit jet, so that it feeds into the cylinder at the place where the two pistonsD come nearest together.

j Patented Oct'. 10, 1916. Application filed' April 12, 1915. Serial No. 20,904.

`In order that the lnvention, whichalso i lcomprises other features hereinafter reffferred to, mayy be.clearly understood and readily carried into effect reference will now be had to the accompanying diagrammatic drawings in which- Figure l illustrates in vertical section, one example of an engine constructed in accordance with the invention, and in which the rear piston is adjustable. 'Fig 2 is a fragmentary view of a modification in which the front piston is adjustable.'

a is the working cylinder, which is fitted with `the two oppositely-moving pistons b and c, of which b is that referred'to as the auxiliary piston, whereas c is regarded as the main piston on account of being nearer to the crank and having a more direct connection-therewith. j

d is the pump cylinder or air compressor, which is formed on the said working cylinder, and has its piston e carried by the piston rod 01 of the lower or main piston o. The area of the pump piston may be one and a half times that of the working piston, more or less. f is the rocking lever or beam, to one end of which the upper. piston is coupled by its connecting rod g, and which is supported by a bracket f1.

'71, is the side-rod which passes through a hole or gap in the frame or standard k, and serves to connect theA other end of the lever f to a yoke or cross-beam z' which extends from a suitably-guided sliding-piece 1. This sliding piece 'i1 may conveniently be guided in the portion j of the frame or standard k, somewhat after the manner in which an ordinary cross-head is guided. The side-rod l1. maybe connected with the said cross-beam by a pin Z.

k1 is a standard or support at the oppov standard 7c.

n is the main connecting rod which is coupled to the yoke or cross-beam z' by a pin and fork arrangement at 11,1 or otherwise, and thus serves to actuate the crank p by the joint impulse of the two pistons. That is to say the lower piston acts through its piston rod 01, while the upper piston acts through the lever f and side rod h on the two opposite ends of the sliding piece or cross-head, and a balanced action is obtained owing to the connection of n being midway between that of L and c1, as shown.

The rear piston may be made adjustable (as above indicated) to vary the clearance or space for containing the explosive mixture. In the example shown, by forming the rod g in two parts which are united by an adjustable connection such as a screwcollar g1 engaging the oppo'sitely threaded ends of the said two parts, the clearance between the pistons can be varied as desired, to suit different fuels for instance. This enables the engine to be adjusted to work economically with either oil or gas as may be convenient without necessarily varying the length of stroke, and without having to remove any of the parts, or to more or less dismount the engine. The side-rod (or rods in case two are used) where it is fitted to the lever f, may have a ball-and-socket or other flexible joint to permit of a little play if necessary, to avoid strain. Thus with a double-piston arrangement, it is possible to use only a single main connecting-rod and crank for both the oppositely-moving pisi tons,'and if three or more cylinders be arranged side by side, there need only be one crank tol each cylinder, justas in a steam engine. It will be seenthat thetop or rear piston can be readily removed by disconnecting the rocking lever or beam, as no cover is` required atthat'end of the cylinder. Two or more cylinders may be arranged in connection with each crank, either opposite each other, or at any other desired angles, and these may be so set that an explosion stroke in one corresponds to a compression stroke in the opposite one.

The pump chamber d forms,` as it were, an enlarged end to the working cylinder, there being a shoulder or off-set part at the junction. It serves for providing the scavenging air, and also a certain amount of air to mix with the fuel to form the charge.

For the sake of simplicity lonly one of each set of ports is shown, that for the eX- haust being shown at m, while that for the scavenging air is shown at m1. The said scavenging air is led from the pump d to the port or ports m1 by any suitable pipe or passage, such as d1, connected with the delivery opening d2 of the pump. The air inlet to thepump 'is indicated at da.

, tially as described.

In the modification shown in F ig 2, the air-compressor el on the lower end o-f the cylinder is omitted, the cylinder being left open at the bottom, just as it is open at the top (see Fig. l). The lower or main piston o is also Vmade adjustable, by threading its rod c1 at the part where it passes through the left-hand end of the cross-head z' (Fig. l) and providing it with two adjusting nuts 02, so that it can be raised or lowered relatively to the cross-head. Thus when an alteration of clearance is required, the top and bottom pistons may each be adjusted by an equal amount.

With a cylinder open at both ends as in Fig. 2, -the employment of liquid supply.

pipes for cooling the pistons is considerably facilitated. In such a case, of course, a separate air pump or compressor is used, operated in any convenient manner.

One or both of the adjacent surfaces of the two pistons are or may be, provided with intermediate recesses or cut-away portions g forming a kind of mouth, channel, or chamber into which the charge from the Vsprayer 1' is injected, this mouth or chamber lying for instance half in one piston and half in the other. This mouth may lead into a spherical cavity or chamber s also formed half in one piston and half in the other, and one piston may have a raised rim or edge t4 to fit in acorresponding vrabbet o r groove t1 in the other, to prevent the compressed charge reaching the cold walls of the cylinder. In some cases however the intermediate recess'may be entirely of wedgeshape, having a rectangular cross-section and a tapering longitudinal section, with the end of the taper near the middle of the piston.l By the use of either a spherical chamber or a wedge-shaped or other recess of this kind, the lworking fluid can more readily enterand act between the pistons.`

Obviously the invention may be modified in various ways in carrying the same into practice without departing from the general nature thereof. I

I claim l. In an internal-combustion engine, the combination of two oppositely-moving pistons, a single'cross-head operated by the joint action of 'said twopistons, and moving in the same direction as one of the pistons, and a crank driven from such cross-head and common to the two pistons, substan- 2 In an internal-combustion engine, the combination of two oppositely moving pistons, a cross-head, guiding means for such cross-head parallel with the pistons, a crank, a connecting rod extending from the middle of saidcross-head, a piston-rod and side-rod connected to opposite ends of said crosshead to secure a balanced action, and a rocking lever for transmitting motion from one 139 'of the pistons to the said side-rod, substaning rod and crank arrangement driven from 10 tially as described. said cross-head, substantially as described. 3. In an internal-combustion engine, the In testimony whereof I ax my signature combination of two oppositely moving pisin presence of two witnesses. tons7 a single cross-head, a roclring lever and v ARTHUR HARRY KOPER PULMN. side rod connectlng the rear plston wlth the cross-head and reversing the motion due to Wtnessess said rear piston, a piston rod connecting the 4I-I. D. JAMESON, main piston therewith, and a single connect- A. NUTTING. 

